Shock absorber



Nov. 10, 1931. J. M. HALL 1,831,173

SHOCK ABSORBER Filed g- 1924 5 Sheets-Sheet 1 J. M. HALL SHOCK ABSORBER Nov. 10, 1931.

Filed g- 1924 5 Sheets-Sheet 2 NOV. 10, 1931. I l HALL 1 ,831,173

SHOCK ABSORBER Filed g- 1924 5 Sheets-Shem 3 M W I Md 77%777Z5E; Wm.

Nov. 10, 1931. .1. M. HALL 1,831,173

SHOCK ABSORBER F l A g- 4. 1924 s sheets-sheet 4 J. M. HALL sHoqK ABSORBER Nov. 10, 1931.

Filed Aug. 4, 1924 5 Sheets-Sheet 5 Patented Nov. 10, 19 31 UNITED: STA-T es i JOSEPH M., HALL; or MmmoNfiONr-mmo;*cAnnnn; nssxcmon T um vnnsnn Imam- GEAR, AT'IAGHMENTiCO A oonmimrlonoFuLmNoIs- I SHOEKQABSOBBERLL Application filedAugust e4, 1924-. Sei=ia1-N0. -.729,ss7.-i

This invention relatesfltol that, type of draft" gears or shock absorbers ,whic h are more particularlyxdesigned for use on railway cars; and in which a pluralit'ygof sets of inter- I F i'g'gi lre 1 is a top plaii view, partlyinisec calated-frictio'n plates are employed Whichtionycf my iniproved; draftgear or: shock "i are adapted to slide lengthwise relatively to I absorbershowing thesa nein' a fullj r'eleased each other, and; which are adapted to;,be or open positions pressed transversely against each other or to I Figure 2 is -a similar view in a fully'clos ed be released from eachothe'rin a tr'ansverse positiohgu direction when applying and releasing the shock absorben p Onecof {the objects of this invention is"- to providea shock' absoriber of high '-capacity' which isinore especially adapted for a rail- Way draftfirigging ,vvher ein a certain free re- 'lease is obtained with Ia'la'rge; friction area showings-he' artsiina fully;closed position of its frictionimembers and a low pressure orrespgndiflg to the position of 'thparts per unit of friction area onthe frictionmemho i Fig g g; i p a a rs, n L Y t H gH mo h- Figurelb isfa side elevation of'one of the graduated action of the parts. f

" Another object of this invention isto-prlo videa mechanism of this characterwhichemf bodies intercalated friction members which v V e Substantiallyvalike' in. constructionalfl Figure? isa vertical. cross sectionrofthddf not attached to the usual followers or a draft t k onlj 'g 7;7- -'Fi 1;"; 1

P as a t r, Par by P 1 Y 1 Figure 8 "s a side elevation: of one'ojf the" I g P 6 constliuctlon as f s tg"Ifriction plates arranged zinlthe'middlpartj repairsand also making aconstruction which. f ne ffh t is very compact. Y

the. draftgean is intended. I

111 the accompanying drawings 5 Whichare in excess of. the capacity for Whfch Figure3 is a sideelevationiof iny iniproved' drafflgear or, shock absorber partly in see- -tion,-and showing, the partsini fu'lly' released V or opienposition corresponding toi-the' posie tion of the parts shown in'Figuretl.

ofthe'setsly I a Figuitefi is anend view'of the draft gear or shock absorber. i

, v a p q a Figiirefi is anyout'er elevation Of/OIIG" off Another oblect t fln t n 5 F thelthrust members or springseats of the ganize the mechanism that When thesame ISJ-thr t i-ing. I V

in operation for absorbing the shock of the 'gu o p lan w a load, a practically uniform frictionload will pa f n h be pl e and the Pr s re a b l Im 9i 1 Figure 11 is'a vertical cross section; taken" t i thrust Sprmg be'utlhted f on. vthe."correspondingly" numbered line? in producinga pressure on the partswhich are Fipumlzl V a V V intendedto frictionally engage each other f g re 1 an Outer elvationvof One; 0i and to release the e from each h theltlirustheadsorwedgeicasings. i i V A further object ofthis invention is to Fig 13: a" topzppla-n g i Same provide a draft'gear. of this character having b i V '-pa1"tlyi insectio'nn V p 7 a, the p y-9 beqommg practlcally Sohd Figurel lisa sideelevation of oneiof the" when a load 15 appliedwto. the same in excess.- 1

wedgegp-latessf F i'gureil is a vieivsiniilar to Figure 3 but 6 frictionuplates arranged at the sideo'f one 7 of that for which the draft/gear is designed and therebypreventsuch an .overf-solidi load 1 from injuring the. absorber whichflFover-e solid limit jis'efiected by means. WhichUa-rei comparatively v simple and 1 inexpensive and. unattached 1 but 7 supported a on parts of? the shock absorber; and thusisenvingsto. protect rth friction elements from damage by; shocks -I' Figure. 15 is. a sid'e'iedgeview offthef latter.

Similar; characters 1; of. reference" indicate}; like parts thrcughoutstheseveral.views, v

Inasmuchlas the" shdckfabsorber. formin the. subjectcof thisfinventioniis symmetrical it j' is immaterial which :endof the device. isjto' i Ward thaendbfthe:car but.mithe follovving 3 description forwconvenience explaining] 0 assumed to mean a return movement of the parts to their normal or relaxed position. The terms forward and backward are to be taken as synonymous with the inward and out so far as the movements of parts in the direction of the length of the shock absorber is concerned.

This draft gear or shock absorber is "adapt ed to be mounted between'two followers 16 and 1'? arranged transversely in the usual and well-known manner between the longitudinal sillsor beams of a carbody, so that these followers are free to move one toward the other in a direction lengthwise ofa car but the extent of the/separation of the same being limited by the usual draft lugs or front stops and the buff lugs or back stops which are arranged on these sills which are engaged by the outer sides of these followers.

The-shock absorber draft gear which embodies my invention is adaptedto be mounted between these followers without being physically connected therewith and thereby permit this gear or absorber to be constructed asa complete unitand inserted as suchbetween the followers when installing the same on "a car and also removed'therefrom as a unit for the purpose of makingrepairs,

This improved draft gear or shock absorber comprises ,two thrust heads or wedge casings 23', 2a which are preferably constructed of cast metal and arranged transversely between the ca-rsills and engaged at their rear or outer sides with the front orinnersides of the followers 16 and 17, respectively.

Each 'o f these thrust heads is provided with a central opening 25 andon horizontally opposite sides of the front or inner end of this opening with front or inner inclined faces 26 which .diverge forwardly or inwardly, as

best shown in Figuresl and 2. 7

Between the two thrust heads are arranged a plurality of longitudinal friction plates 27 which constitute, two sets, themembers of one set alternating with those of the other so that they are intercalated. The opposite ends of these two sets of friction plates are arranged within the central openings 25 of the two thrust heads and at times the rear ends of one of these sets of friction plates engagewith the front or inner side of one of'the followers and the rear or outer ends of the other set of friction plates engage with the front or inner side of the other follower so that these plates are compelled to move'longitudinally forward or inward with thefollowers, while at other times the rear or outer ends of these friction plates are spaced apart from the respective followers for a purpose which will presently appear. Each of these friction plates is provided on the rear 'or outer portions of its longitudinal edges with forwardly or inwardly facing shoulders 28, these shoulders being formed'by makingthe rear or outerends of these plat-es wider than the front or inner parts thereof. 1

At opposite flat sides of the ends of the two sets of friction plates are arranged two pairs of wedge plates 29 and 30, members of each pair being arranged transversely opposite each other and engaging their inner longitudinal flat sides with the adjacent friction plates to produce a variable pressure upon the samejand cause them to engage each other with varying degrees of friction and thus resist relativelongitudinal movement of thesamea'ccordingly- The'members of each pair ofjwedgeplates are coupled with one of the thrust heads so as to be compelled to move lengthwise therewith most of the time and also .to produce a wedging action of each thrust head against the respective pair of wedge plates at the corresponding end of the sets of friction plates during the forward or inward movement of the thrust head and thereby not only move the respective wedge plates forwardly or inwardly, but also press the same transversely inwardly so that the friction plates are [pressed together and engage each other with increased frictional contact. This is preferably effected bylproviding theouter side of'each wedge plate with a laterally projecting rib 31, therear or outer side of whichhas an inclined face 32, the two inclines of the companion wedge plates at the same end of the draft gear diverging forwardly or inwardly, and engaging respectively with theforwardly or inwardly diverging inclined faces 26 of the respective thrust head, as shown in Figures 1 and 2. On its front or inner side the rib 31 of each wedge plateis provided with an inclined face 33,

these faces of thecompanion wedge plates be- 3 ing so arranged that they vconverge forwardly or inwardly.

Surrounding each pair of wedge plates and the adjacent end of the two sets of intercalated friction plates is a thrust member or spring seat 3i which hasthe form of an oblong frame the opening 35 of which receivesthe adjacent pair of wedge platesand the parts of the friction plates which are arranged between these wedge plates, as best shown in Figures 1, 2, 3, f and 11. The vertical inner edges of each of these thrust members or: spring seats are provided with inclined faces 36 which diverge rearwardly or outwardly and engage respectively with the forwardly or inwardly converging inclined faces 33'on the adjacent wedge plates, so that a wedging engagement is produced between these parts upon-effecting 'a relative longi ject rearwardly or outwardly into'the opening'25 of the adjacent thrust head along the upper and lower sides of the adjacent end of the two sets of intercalatedfriction plates and adapted to engage with the forwardly or inwardly facing shoulders 28 at the rear or Y outerend of one of' these sets, as shown in upper and lower edges of the horizontal parts r Figures 3 and 4. The forward or inward movement of each of the thrust members or spring seats 34 is effected by engagement therewith of the ribs 31 on the adjacent wedge plates during the forward or inward movement of the latter. The outward return or backward movement of each'thrust member or spring seatis effected by spring'pressure during-a normal'relaxaftion ofthe draft gear or shock absorber but forthe purpose of com pelling each of these thrust members and the wedge plates and friction plates associated therewith to move longitudinally backward or outwardtherewith at certain times, coupling means are provided which preferably consist of coupling or stop hooks 38 arranged on the of the thrust member or'spring seat-and. pro- U jecting rearwardly or outwardly therefrom so that the inwardly or forwardly projecting beaks or bills 39 form forwardly or inwardly facing shoulders 40 which are adapted to be engaged by rearwardly or outwardly facing "5- shoulders or stops 41 formedon the front or inner edges of the opposite vertical sides of the respective thrust head, as shown in Figures 3 and 4. Y

The numeral 42 'representsja thrust-spring I or main wedge spring which is preferably of helical form and surrounds thecentral parts of the friction plates and the inner or front ends of the wedge plates and bears at its op posite ends against the opposing flat faces ,1; 43 on the front or inner sides of the thrust members around the openings 35 thereof, as

shown in Figures 1 to 4.

Resilient means are provided which operate constantly to move the thrust heads and the followers with which they engage outwardly, rearwardly or apart from each other for the purpose of releasing the draft gear or shock absorber. In the preferred form "of these means, as shown in the drawings,

the same comprise two helical releasing At its opposite ends. each of the releasin springs 44 bears against seats 46 formed on' springs 44 which are arranged lengthwise on horizontally opposite sides of the main or thrust spring 42 and each of these releasing springs passing near its opposite ends through openings 45 formed in the corresponding ends of the thrust members 34 so as to form a guide and support for the latter.

' the corresponding portions of thefrontor inner'sides of'the two thrust heads 23, 24, as

shownin Figures 1 and 2'. r V

The thrust heads 23, 24 are prevented from separating an undue extent when the-draft gear is removed from the car by means which preferably comprise two tie rods 47, each of which extends lengthwise through one of the releasing springs 44 and openings 48 in the correspond.-

ing parts of the two thrust heads and is provided at opposite, ends with shoulders 49, 50 which face forwardly or inwardly, and engage with the rear or outer sides of the thrust heads 23, 24 thistie rod being preferably constructed in the form of a bolt, the

head andnut of which form the shoulders 49 and 50 just referred to. The rear or outer sides of the thrust heads 23, 24 are provided with recesses 51 which receive the shoullimited by positive means so as to prevent theishock absorber from being, overloaded when subjected to a load beyond the'oapacity of the shockabsorber. This is accom plished in the present instance by the use of a plurality of stop members 52 which are constructed in the form-of solid rods or posts i and arranged lengthwise along different parts circumferentially of" the draft gear. '1 In the preferred form two of such stop rods or posts 52 are-arranged on opposite sides of eachof the releasing spring-s44 adjacent to the outer side of the thrust or wedge spring 42, eachof these stop rods or-posts passlng near 1ts opposite ends loosely through guide openings 53 formed in the marginal parts of the thrust members or spring seats 34, and also adapted to be engaged at its opposite ends by forwardly or 1 inwardly facing shoulders or abutments 54 arrangedon the adjacent marginal parts of the corresponding sides of the twoothrust heads 23, 24,-as bestshown in Figures 1 to 4.

Each of these stop rods or posts is of less length than the distance between the corresponding shoulders '54 of the two thrust heads when the latter are separated to their c maximum extent when the draft gear or shock absorber is in its fully released condition. This difference between the lengthof the stop rods and the distance between the shoulders 54 of the two thrust heads reprev i sents the amount of movement whichthe two thrust heads can effect toward each other when closing the shock absorber, and

when this has been exhausted the stop shoulders 54 of the two thrust heads engage with opposite ends ofthe severalstop'rods 52 and render the draft '7 gear practically solid.

Each of the stop rods 52'fioats freely in the guide openings 53' of the thrust member 34 and is capable of moving lengthwise therein in either direction'depending upon whichever thrust head is moved forwardly or inwardly. V

In order to adapt the intercalated friction plates generally to the shape of the space within the main thrust or wedge spring 42 those plates of both sets which are arranged in the central part ofthis space are made of the same widththroughout from the shoulders 28 at the rear or outer ends thereof up to the front or inner ends of these plates, as shown in Figure 8, whereby these plates can be made of approximately maximum width and thus ensure a comparatively large frictional area contact between the wedge plates in the center of the mass of plates, whereby a large resisting effect is obtained when these plates are slid relatively to each other. Those plates of both sets, however, which are arranged-adjacent to the outer or lateral sides of the mass of plates are made somewhat narrower on the front or inner parts thereof, as shown at 55 in Figure 5, so as to permit these plates to occupy the comparatively narrow space within the main thrust or wedge spring adjacent to the inner sides of the wedge plates or shoes 29, 30, as shown in Figure '7, thereby permitting ofutilizing the space within the spring to greater advantage and increasing the capacity of the shock absorber accordingly.

In order to'facilitate assembling'of the parts of the absorber and prevent the wedge plates from slipping forwardly through the thrust members at this time, each of the wedge plates is provided on the rear or outer parts of its longitudinal edges with laterally projecting stop lugs or shoulders 56 which are adapted to engage the rear or outer stop faces or shoulders 37 on the respective thrust member or spring seats, this relative position of these parts being shown in Figures 3 and 4. These lugs also serve to guide the wedge plates and keep the same centrally within the main or thrust spring and in proper engagement with the outermost friction plates inasmuch as the side ends of these lugs are arranged close to and are adapted to engage with the inner vertical sides of the openings 25 in the thrust heads, as shown in Figures 3 and 4:.

The front or inner sides of the thrust members are provided with curved centering ribs 57 which engage with the periphery of the vVhen the several members of the shoclr absorber are fully assembled and placed in the draft rigging of the car, the main thrust --movable follower.

or wedge spring and r'elease'springs are nuder an initial compression in the fully re leased oropen position of these parts. The tie rods serveto limit the relaxation or opening movement of the shock absorber and also serve to hold the several complete unit.

If a load is now applied to either or both of the followers and the thrust heads 23 and 24: engaging against the inner front sides thereof sufficient to overcome the initial tension of the springs of the shock absorber, these thrust heads and followers will be first forced one toward the other lengthwise of the gear, independently of the friction plates,

thereby compressing the main thrust or wedge spring and the release springs. The thrust or wedge spring at this time creates a pressure against the thrust members or spring seats in a rearward outward direction toward both followers. The thrust members or spring seats exert a backward or outward pressure against the wedge plates through the medium of the cooperating inclined surfaces 33 and 32 of the wedge plates andthrust members 84. This produces a wedging action of the thrust members 34 against the wedge plates whereby the latter are pressed transversely inwardly against opposite sides of the two sets of wedge plates, whereby an increased pressure is produced between the cooperating surfaces of the friction plates. During the continued forward or inward movement of one follower toward the other, thefront or inner sides of the followers engage the rear or outer ends of the friction plates so that thereafter one set of friction plates moves forwardly or inwardly with the Increased frictional resistance is offered against such sliding movement due to the increased" lateral pressure of these friction plates against one another by reason of the wedging action of the thrust heads and thrust members 31 against the wedge plates 29 and This frictional resistance increases in the same measureas the thrust heads approach each other so that a gradually increasing friction resistance is offered to closing movement of the gear. The limit of such movement is reached when the front or inner abutment surfaces 54: of both thrust heads 23 and 24 engage with the opposite ends of the stop rods or posts 52 at which time the shock absorber is solid and no further closing or cushioning effect of the same occurs, thereby. preventing injury to any parts of the absorber in the event that a shock or blowlis given to the absorber which is in excess of the capacity for which the particular shock absorber is intended.

If now the load on the followers and thrust heads is released or is lessened below the capacity of the release springs, the latter will force the thrust heads or wedge casings 23 and 24 and the followers engaging thereparts together as a,

.37 -ontth'eispring seats comezin contact With- "theshoulders 28 on thefriotion-lplatesj Thei mmaina thrust OII'VVQClgEB spring *42'then tends a :toe retract aor. :move the friction plates'ha'elo- 'wardly or. outwardly while therelease springs w tend :toreleaseirthe wedging: engagement zof'i the ithr-ust' heads T23 and 24 "from the" rear 1 1 or outerwinclinedi surfaces 32 on the: We dgea plates. \Vhen this Wedging' aotionuis suf-- wficiently relieved theamain 1 thrust on wedge .jspring mVes-'the fricti0n plates backward- I 1y oroutwardly which tends to force a the thrust heads and followers-apart or back- I wardly or I outwardly inasmuch as there is i more pressure "exerted bythe main or Wedge spring than is'neoessa-ry to bIlHQ tlIE'fTEG' tion 'plates backWardly-or outwardly to their released position. This releasing movement of the draft *gear continues until the rear- -or outer faces of' the-thrust heads 23- and 524 engage with the shoulders 49 and-- 50 on the tie rodsat which time the shock absorber is in its fully ope1-1ed or 1 released position= but still und'er the initial tension which :has

been put into the :same When assembling. 'the parts. 5 The engagement of theshoulders:

' or stops 37 on the thrustunembers is 'eil'ectjed while the latterunove loackwardly -or-out-v "Wardly a sufficient "extent for this purpose i independently; of *the -triotion plates, but' 351 thereafter the thrust members and: friction plates move backwardlyworoutwardly -together until the gear is fully opened. Dur- 1 ing this opening movement the front or innersides of the followers are I also-again: dis- 9 engaged from' the rear or -outer ends oh the I friction plates. l I

I claim as my invention: 7 13A shock absorber comprising thrust 1 heads movabl'e lengthwise relatively to each other, wedge' plates engaging with said thrust heads, intercalated" frictionplates adapted toi a be pressed together by s'a'id wedge plates,

l thrust me'mhers having Wedging engagement 'with said'wedge plates, aithrustspring in terposed between saidthrust -members, v --leasingsprings interpos'ed betweensaid' thrust heads, stop rods --1 mounted on said .thrust members and 'adapted to-be engaged by said thrust headsfor limiting the closing -movement ofthe absorber and means for causing'st-he friction platesyto move relative r :tO- eachothemoncompression and-"on release;-

2. A shoolrabsorher eomprising th-rust 0 heads movable lengthwise relatively to each "othemwedgeplatesengaging Withsaid'thrustheads; interc'alatedfiat friction plates adapt- -'ed to be pressed together by said wedge plates,* thrust -menibers having 'Wedging en- -gagement With-said wedge plates, and-hav-r -ing guideppenings, athrustspring intersand adapted todae engagedby-vsaid thrust release.

:posed: between E saidvthrustwmembers; releas- 2 ring springs; iinterposed=-between said rathrust :aheads, stop rods; arranged .;lo,os ely in a said vcopenings :ofythe thrust members and adapted to be engaged: atopposit'e endsby said thrust v'heads and means :fOIf' causing-the friotion plates :to move relative to reach other I on oom- -pressionand-on release.' Y i v T a 3.= A shock absorber; 5 comprising thrust dreads movable -lengthwi se relatively to each =0t'l1er, Wedge plates-having Wedging engage- I :rmentx with "said thrust heads, interoalat'ed lrflflt *frictionplates adapted; to be pressed together bywsaidr Wedge plates, thrust mem- --:bershaving Wedging vengagement with said 5 -Wedge plates, arthrust. spring interposed hetween 'sa id' thrust-members; releasing springs ."interposed 5 between :said: thrust 1? heads,

'stop rods-amounted on saidthrust-meinhers heads for: limiting the closing movement of the absorber and means 'foracausingl the; friction: plates r to .move' irelative to reach other oni'compressio'n and vonureleaseQ I v 7 42 A- E shock absorber --'eomprising. athrust lillQEtdS amovable lengthwise relatively to leach 1 other, wedge pl'ates engaging Withtsaidthrust heads,- a single column of:intercalate'defrio tion 'plates between said Wedge plates adapted to'be pressed together hysaid'wdge p1ates "thrust members having ivedeing'iengagement 1 with; saidWedgeplates and hav ng openings,

a :thrust spring:iinterposed' between said "thrust members, releasing sp'rlngs passing through said :openings 1 and interposed be @3100 tween said-thrustiheads' and means for'eausingthefriction plates tomove relative to each other -=on compression and on "release.

5. A shock 1 absorber "comprising'kthrust heads movable lengthwise relatively. to each- I other, Wedge iplates engaging with" said thrust heads; :interealated flatr friction plates adapt-1 ed to be pressed together "bygsaid Wedge plates,v thrustnmembers having: Wedging en- 'gagementwith said wedge iplates. and hav wing a plurality otopening s, thrust spring uinterpos'ed between said thrust members; re- Y leasing springs*passingrthrough"someofsaid openings. and interposed between said thrust ;heads,-stop rods arranged in others of said :openings and adapted to; be engaged at opposite ends by said thrust -heads'and': means for pausing the "friction" plates to move relative'to each-other on fcompre'ssion and on I -6LA shockwiabsorber comprisinga plu- -rality fof sets of' intercalated fiat friction "plates," wedge plates engagingwvith opposite lateral sides of said sets ofrfiriction platesythrust": heads movable =relatively to each other and provided-with openings receiving said frictioniplates andwedge plates and engaging with said Wedge "plates, thrust members havingopeningswhichreceive said friction plates and'wedge plates and having wedging engagement with' the latter, a thrust fsprmg surrounding the friction plates and wedge plates and: engaging with said thrust members, releasing springs interposed between said thrust heads and means for causing the friction plates to move relative to each other'on compression and on release.

7. A shock absorber comprising a plurality of sets of intercalated-flat friction plates,

wedge plates engaging with opposite lateral sides of said sets of friction plates, thrust heads movable relatively to each other and sides of said sets of friction plates, thrust heads movable relatively to each other and provided with openings receiving said friction plates and wedge plates'and engaging with said wedge plates, thrust members having openings which rece ve said friction plates and wedge plates and having wedging engagement withthe latter, and having stop shoulders which project rearwardly into the openings of said thrust head and adapted to engage with forwardly facing shoulders on said friction plates, a thrust spring surrounding the friction plates and wedge plates-and engaging with said thrust members, releasing springs interposed between said thrust heads and means for causing the friction plates to move relative to each other on compression and on release.

9. A shock absorber comprisinga plurality of sets of intercalated friction plates, wedge plates engaging with opposite lateral sides of said sets of friction plates. thrust heads movable relatively to each other and provided with openings receiving said friction platesand wedge platesand engaging with said wedge plates, thrust members having openings which receive said friction' plates and wedge plates and having wedging engagement with the latter, and having forwardly facing shoulders adapted to engage with rearwardly facing shoulders on said thrust heads, a thrust spring surrounding the friction plates and wedge plates and engaging with said thrust members, releasingsprings interposed between said thrust heads and means for causing the friction plates to move relative to each other on compression and on release.

10. A shock absorber comprising aplurality of sets of intercalated friction plates,

wedge plates engaging with opposite lateral sides of said sets of friction plates, thrust heads movable relatively to each other and provided wlth opemngs receiving sald fric;

tion plates and wedge plates and engaging shoulders which project rearwardly into the openings of said thrustheadand adapted to engage'with forwardly facing shoulders on said friction plates, a thrust spring surrounding the friction plates and wedge plates and engaging with said thrust members, releasing springs interposed between said thrust heads and said wedge plates having laterally projecting lugs at their rear ends which are arranged within the openings of said-thrust heads and in rear of the shoulders of said thrust members and means for causing the friction plates to move relative to each other on compression and on release;

11. A shock absorber comprising a plurality of sets ofintercalated friction plates,

wedge plates engaging with opposite'lateral sides of said setsof frictionplates, thrust heads movable relatively .to each other and provided with openings receiving said friction plates and wedge plates and engaging with said wedge plates, thrust members having openings which receive said friction plates and wedge plates and having wedging engagement with the latter, a thrust spring surrounding the friction plates and wedge plates and engaging with said thrust mem bers, and releasing springs interposed between said thrust heads, the inner ends of the friction plates in the central part of the thrust spring being comparatively-wide and r;

the friction plates adjacent to opposite sides of said thrust spring having their inner parts made comparatively narrow, said elements being organized for causing the friction plates to move relative to each other on compression and onrelease. v .7

' 12. A shock absorber comprlsmg a plurality of sets of intercalated friction plates,

wedge plates engaging with opposite lateral sides of said sets of friction plates, thrust heads movable relatively to .each other and provided with openings receiving said friction plates and wedge plates 'and'engaging with said wedge plates, thrust members having penings which receive said friction plates and Wedge plates and having wedging engagement with the latter, a thrust spring surrounding the friction plates and wedge plates and engaging with said thrust members, and'releasing springs interposed be tween said thrust heads, the inner sides of said thrust heads being provided with centering ribs which hold the thrust .spring against lateral displacement relatively thereto, said'elements being organized for cans 1.

ing the friction plates to moverelative to each other on compression: and on release. I

13. Ashock absorber comprising a plurality: of sets of intercalatedflat friction plates, wedge plates engaging with opposite lateral sides of said sets of friction plates, thrust heads movable relatively to each other and provided with openings receiving said friction plates and wedge plates and engaging with said wedge plates, thrust members having openings which receive said friction plates and wedge plates and having wedging engagement with the latter, a thrust spring surrounding the friction plates and wedge plates and engaging with said thrust member releasing springs interposed between said thrust heads, and followers adapted to engage the outer ends of said friction plates, said elements being organized for causing the friction plates to move relative to each other on compression and on release.

14. A shock absorber comprising thrust heads movable lengthwise relatively to each other, wedge plates engaging with said thrust heads, intercalated flat friction plates adapted to be pressed together by said wedge plates, thrust members having wedging engagement with said wedge plates, a thrust spring interposed between said thrust members, releasing springs interposed between said thrust heads, stop'rods mounted on said thrust members and adapted to be engaged by said thrust heads for limiting the closing movement of the absorber, and followers adapted to engage the outer ends of said friction plates, said elements being organized for causing the friction plates to move relative to each other on compression and on release.

15. A shock absorber comprising a plurality of sets of intercalated friction plates, followers adapted to engage the outer ends of said friction plates, wedge plates engaging with the outer lateral sides of said sets of friction plates and each having inner and outer inclined faces, heads engaging the inner sides of said followers and each having inclined faces engaging the outer inclined faces of the wedge plates at one end of said friction plates, thrust members each having router inclined faces engaging with the inner 'mclmed faces of the wedge plates at one end of said friction plates, a wedge spring on gaging the inner side of said thrust members and surrounding said friction plates, releasing springs engaging with the inner sides of said heads and passing through said thrust member, tie rods extending through sait releasing springs and having shoulders their ends which bear against the outer side of said heads, and stop rods mounted on said thrust members and adapted to engage their opposite ends with the inner side of 'saic heads, said heads having outer shoulders, said thrust members having retaining hooks 'terior of said adapted to engage said shoulders, and the friction plates of each set having inwardly facing shoulders adapted to engage an outwardly facing shoulder on oneof said thrust members,

716'. In a friction shock absorbing mechanism, the combination with a group of'intercalated, relatively movable, longitudinally disposed friction piate'si wedge friction shoes at the opposite ends of said plates, said shoes beingdisposed at opposite sides of the group of plates; spring resistance means eX- lowers interposed betweensaid spring resistance and the shoes atthe opposite ends of the plates, said followers having, means thereon engaging said plates for returning them to normal position; and relatively movabie main followers having wedge means associated therewith, forcin said shoes toward a.

plates into tight frictional engagement with each other during a compression stroke, and spring resistance elements including aspring encircling'said fllQJlOIl plates for resisting the compression of said gear, and other spring means engaging said followers for moving the same outwardly longitudinally of the gear for releasing said lastalamed means, and for restoring said followers to normal release-position upon the release of ear.

18. Adraft gear comprising a pair of followers, spring means engaging said followers for resisting compression of said gear, a centrally disposed column composed of a plurality of sets of intercalated fiat friction plates which engage each other, and are movable lengthwise relatively to one another, press ing means including wedging slices engaging the outermost plates, and a thrust member having wedging engagement with said shoes at opposite ends of said column for pressin said plates together during a compression stroke, and rneansincluding a spring resistance arranged externally of and surrounding said column for resisting the longitudinal movement of said plates during a compression stroke and to restore said plates to'normal position after each compression of the gear. I g

19. A draft gear comprising a pair of followers, spring means enga ing said followers for resisting compression of said gear, a cengroup of plates; spring foling means and thrust member, and means for restoring the plates to normal position after release.

20. A draft gear comprising a plurality of sets of intercalated flat friction plates, followers adapted to engage the outer ends of said sets of plates, wedge plates movable lengthwise with said followers and engaging with the outer sides of said friction plates, thrust members having wedging engagement with said wedge plates, a thrust spring surrounding said friction plates and engaging said thrust members, and means for returning the plates to normal or released position.

21. A draft gear comprising a plurality of sets of intercalated flat friction plates, followers adapted to engage the outer ends of said sets of plates, wedge plates movable lengthwise with said followers and engaging with the outer sides of said-friction plates, thrust members having wedging engagement with said wedgeplates, a thrust spring surrounding said friction plates and engaging said thrust members, releasing spring means interposed between said followers and arranged outside of said thrust spring, and means for returning the plates to normal or released position.

22. A draft gear comprising a plurality of sets of interoalated fiat friction plates, followers adapted to engage the outer ends of said sets of plates, wedge plates movable lengthwise with said followers and engaging with the outer sides of said friction plates, thrust members having wedging engagement with said wedge plates, a thrust spring surrounding said friction plates and engaging said thrust members, releasing spring means interposed between said followers and arranged outside of said thrust spring, a tie rod extending through said releasing spring means and connecting said followers, and means for returning the plates to normal or released position.

23. In a draft gear, a pair of followers, a single group of two sets of longitudinally movable intercalated fiat friction plates between said followers, wedging means at each end of said gear at each side of said group of plates for forcing said plates laterally inward during the compression of said gear, resilient means for resisting the compression of said gear, springs engaging said followers for resisting the compression of said gear and for separating said followers when said said gear.

JOSEPH M. HALL,

iii)

CERTIFICATE OF CORRECTION.

Patent No. 1,831,173. Granted November 10, 1931, to

JOSEPH M. HALL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 6, line 22, claim 7, after the word "heads" insert the words and means for causing the friction plates to move relative to each other on compression and on release; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 22nd day of December, A. D. 1931.

I M. J. Moore, (Seal) Acting Commissioner of Patents. 

